Pencil with self-refilling cartridges

ABSTRACT

A writing implement in which a plurality of short cartridges are arranged in order in a hollow of an elongate plastic tubular casing, said cartridge having a short presharpened lead at its front end and a hole at its rear part and having an outside diameter so as to be received in frictional relationship in the hole and when the short lead that is normally exposed at the front end of the tubular casing has become blunt or broken, the front-most cartridge can be readily removed by pulling it out of the front end of the tubular casing characterized in that several lines of slits reaching into the hollow inside of the plastic tubular casing at its rear end are formed in the longitudinal direction of the tubular casing, and resilient members that are continuous with the tubular casing but are mutually divided are formed by the slits, and engaging edges that are curved inwardly of the hollow are formed at the rear ends of the resilient members, and the rear end of the cartridge inside of the tubular casing is locked by the engaging edges to prevent retraction of the cartridges by the application of pressure during writing operation.

@hiwChih [451 Sept. 25, 1973 lPENCHL WITH SELF-REFKLLKNG CARTRIDGES 57] ABSTRACT A writing implement in which a plurality of short car- [76] Inventor: Chuehg chinchihg 9 tridges are arranged in order in a hollow of an elongate n g Talwani plastic tubular casing, said cartridge having a short pre- Chma mama sharpened lead at its front end and a hole at its rear part [22] Filed: Man 7 1972 and having an outside diameter so as to be received in frictional relationship in the hole and when the short PP 232,577 lead that is normally exposed at the front end of the tubular casing has become blunt or broken, the front- [52 us. Cl. 401/57, 401/82 meet Cartridge be readily removed by pulling it out 51 im. Cl B43k 21/14 of the from end of the tubular easing ehereeterized in 58 Field 0t Search 401/57, 8284, that Several lines efehte reeehihg into the hollow inside 401/67, 9] 97 of the plastic tubular casing at its rear end are formed in the longitudinal direction of the tubular casing, and 56] References Cited resilient members that are continuous with the tubular casing but are mutually divided are formed by the slits, UNITED STAT ES PATENTS and engaging edges that are curved inwardly of the hol- 3.738.235 1/1973 Kolomier .r 401/57 low are formed at the rear ends of the resilient 7 i t d bers, and'the rear end of the cartridge inside of the tu- 55 5 8/1967 f 401/82 bular casing is locked by the engaging edges to prevent w retraction of the cartridges by the application of pres- Primary Examiner-Lawrence Charles Sure durmg wmmg Operation Att0rney-Berman, Davidson and Herman 5 Claims 6 Drawing Figures 1 [ll 1 3 ll] 2 1L 8 JL/V/ PATENTED Z B SHEET 1 0F 2 PRIUR ART l PENCIL WITH SELF-REFILLING CARTRIDGES The present invention relates to writing implements, and more particularly, to a pencil which is characterized by a suitable number of pre-sharpened leads carried by cartridges contained in a tubular holder and which leads may readily be replaced with fresh presharpened leads contained in said tubular holder. The conventional concrete example is shown in FIG. 1 where a cylindrical cartridge has a pre-sharpened writing implement constituted by a lead 2 disposed coaxially at one end thereof. A cylindrical pencil holder casing 3 is made of plastic material and has a coaxial bore 4.

A plurality of cartridges 1 are prepared and inserted sequentially in the bore 4 of the pencil holder 3. Each cartridge -1 has a bore 5 in the rear end thereof to accomodate the pre-sharpened lead 2 of the succeeding cartridge arranged in abutting coaxial relationship. A rear sleeve 6 made of similar plastic material is inserted and screwed into the inner rear end portion of the tubular casing 3. The sleeve 6 has a thin projection 7 curved inwardly at its front end with respect to the casing.

The projection 7 prevents rearward retraction of the cartridges 1 from the casing 3 upon the application of pressure to th foremost cartridge during a writing operation.

In the manufacturing process of the known pencil, the work of threading the sleeve 6 into the tubular casing 3 is troublesome manual work. Also, the tubular casing 3 and the sleeve 6 are produced by separate metal moulds, whereby the costs of production become higher and, furthermore, in case of using transparent resin materials for making the tubular casing, the threaded portion between the sleeve and the casing is visible from the outside to produce an unfavourable appearance to the pencil.

The projection 7 which is positioned inside of the tubular casing 3 is inwardly curved and thus the projection 7 is urged against the inner wall of the bore 4 due to the cartridges being loaded successively into the pencil; Such loading causes the projection 7 to lose resilience, and also lose the positive action as a means of preventing rearward movement of the cartridges in the pencil.

According to the present invention, there is provideda writing implement comprising a tubular casing; a plurality of slits in said casing, said slits extending longitudinally with respect to said casing and formed in an end portion of said casing, a portion of casing between adjacent slits constituting a resilient material; a rim extending inwardly with respect to said casing and formed on at least one of said resilient materials; at least one cartridge carrying a writing element for projection beyond said casing at the other end thereof, said cartridge being permitted insertion to said casing through one end of said casing and removal from one end only of said casing, the or each said cartridge being adapted for engagement with another cartridge in abutting axially aligned relationship thereto; means providing frictional engagement between said casing and the or each said cartridge, said means permitting relative movement between said casing and the or each said cartridge; the arrangement being such that in use, the writing element project s beyond said other end of said casing and the or each said cartridge is restrained from removal from said casing by said frictional engagement and said rim,

said rim engaging one end of the or an adjacent cartridge by the application of pressure on said cartridge during the writing operation.

In a preferred embodiment, the implement comprises four said slits, said slits being disposed equiangularly around the casing axis. Particularly, two of said resilient material are oppositely disposed to each other with respect to the axis of the casing said two resilient materials each having a greater longitudinal dimension than the other two resilient materials, and said two resilient materials each having one said rim formed thereon.

Conveniently, the axially inner surface of said rim is coplanar with the axially outer surface of each of said other two resilient materials.

Advantageously, the casing is formed of a plastic material.

Preferably, the implement includes a plurality of said cartridges disposed sequentially within said casing, each cartridge having an axial bore to accommodate said writing element of a succeeding cartridge. The or each cartridge has an axially extending protrusion disposed on the outer periphery of the cartridge, said protrusion permitting guidance of said cartridge within said casing.

The frictional engagement means comprise an annular member formed of an elastomeric material, said annular member being disposed within said casing towards said other end.

The present invention will now be described by way of example only with reference to the accompanying drawings in which:

FIG. 1 is a side section of a known pencil showing a part of one cartridge in section;

FIG. 2 is a side sectional elevation of one embodiment. of the invention showing a part of one cartridge in section;

FIG. 3 is a perspective view in part section of FIG. 2;

FIG. 4 is an enlarged perspective view of part of another embodiment of the invention; and,

FIG. 5 is a cross sectional view taken along the line AA of FIG. 6. FIG. 6 is an end view of rear sleeve.

Referring to FIGS. 2 and 3, a writing implement comprises a cylindrical casing 3 having a stepped bore 4 terminating in a portion 11 of enlarged diameter at the front end portion of the casing. The casing 3 has four equal and parallel slits 8 formed in the rear end portion. The slits 8 are parallel to the longitudinal axis of th casing 3 and are angularly spaced around the axis of the casing 3. The stepped portion 11 has an annular friction member 12 inserted therein, the member 12 being formed of an elastomeric material such as rubber or a soft synthetic resin. The portion of casing 3 between two adjacent slits8 constitutes a resilient material 9 and, as shown in FIG. 3, there are four resillient materials 9. The rear end of each resilient material 9 has an arcuate rim 10 which extends radially inwards with respect to the casing axis.

The writing implement includes a plurality of cartridges 1, each cartridge 1 being constituted by a cylindrical element including a coaxial stepped bore 5, the free end of the bore facing rearwardly with respect to the implement. The front end of the cylindrical element has a coaxial cylindrical extension, of lesser diameter than the cylindrical element, the extension extending forwardly with respect to the implement, the extension carrying a coaxially aligned writing element such as a pencil lead 2. The arrangement is such that when a plurality of cartridges 1 are loaded sequentially into the casing 3, the stepped bore accomodates the lead 2 and extension of the succeeding cartridge 1 in coaxially aligned abutting relationship. The radially outer peripheral surface of each cartridge 1 has four protrusions extending longitudinally, the protrusion being equi-angularly spaced around the axis of the cartridge. The protrusions constitute guide means for each cartridge 1 in the bore 4, and frictionally engage the annular member 12 when the cartridge 1 reaches the foremost position in the implement. It will be understood that the foremost position is the position where a cartridge is in the operative position for writing. The rearward end of the rearmost cartridge 1 is positioned axially inwards of the rims such that pressure on the loaded cartridges in the rearward direction forces the rearward end of the rearmost cartridge against the rims 10. The reaction of the rims 10 against the rearmost cartridge prevents the rearmost cartridge from leaving the rear end of the implement when such pressure is applied.

lt will be understood that the annular member 12 restrains cartridge 1 from leaving the implement through the front end thereof by means of the frictional resistance between a cartridge 1 and the member 12 fixed to the casing 3. Preferably, each slit 8 has a longitudinal dimension in the range of 1 cm to 1.5 cm.

in operation, when the lead 2 of a cartridge 1 is broken or blunted, the defective cartridge 1 is removed from the implement through the front end thereof. The defective cartridge is discarded and a new cartridge is loaded into the implement through the rear end thereof so as to move longitudinally the cartridges already loaded in the implement towards the front end until a fresh lead 2 projects axially outward from the implement. Alternatively, the defective cartridge 1 may be inserted into the rear end of the implement so as to move the fresh cartridges forwardly in similar manner. Due to the resilience of the resilient materials 9, a cartridge may be inserted into the rear end of the implement so as to pass axially inwards past the rims 10. To assist the insertion of each cartridge 1 into the bore 4 so as to be clear of the rims 10, it is necessary to insert a finger nail into one or more of the slits 8 so as to engage the rearward end of the cartridge being inserted and force it axially inwards of the rims 10.

In another embodiment of the writing implement as shown in FIGS. 4 and 5 of the drawings, two oppositely disposed resilient materials 9b and 9d are shorter than the remaining resilient materials 9a and 9c.- The materials 9b and 9d do not include the rim l0, and the axially outer surface of materials 9b and 9d lie in the plane which contains the axially inner surface of each of the rims 10 carried by materials 9a and 9c. Thus, insertion of a cartridge 1 inwardly past the rims 10 may be assisted by use of a finger tip pushing the rear end of the cartridge until it lies flush with the axially outer surface of the materials 9b and 9d; in this position, the cartridge 1 will be clear inwardly with respect to the rims 10, which rims will restrain rearward mvement of cartridges 1 with respact to the casing 3. It will be understood that only one rim 10 may be used in this embodiment, but it is preferred that two be used to ensure restraining of the cartridges against rearward movement thereof relative to the casing.

in this embodiment, the dimensions of the resilient material 9 may be arranged such that the axially inner surface of each rim 10 is spaced axially outwards with respect to the axially outer surface of materials 9b and 9d.

It has been found that the embodiments described result in a more simple manufacturing process compared with known writing implements of this kind.

What is claimed is:

1. A writing implement comprising a one-piece tubular casing having a bore extending from its front end to its rear end, a plurality of slits formed in said casing, said slits extending longitudinally forwardly from the rear end of said casing to define short strips of resilient material between adjacent slits and which constitute the rear portion of the casing, an inwardly extending rim formed at the rear end of at least one of said strips of resilient material, a plurality of cartridges positioned in end-to-end abutting axially aligned relationship in said casing, each of said cartridges carrying a writing element at its forward end, said cartridges being individually insertable into said casing through the rear end of said casing by spreading said strips of resilient material radially outwardly and being individually removable from the front end of said casing, and friction means provided in an enlarged portion of the bore of the casing at its front end and frictionally engaging the forwardmost cartridge to hold it in the casing while permitting relative movement between said casing and the forwardmost cartridge when insertion or writing force is applied to the cartridge, the arrangement being such that in use, the writing element of the forwardmost cartridge projects beyond said front end of said casing and is restrained from rearward movement by the abutting condition of the remaining cartridges and the engagement of the rearmost cartridge with said rim, said rim engaging the rear of the rearmost cartridge as a stop to further rearward movement upon application of pressure to the cartridges during the writing operation.

2. The writing implement as claimed in claim 1, wherein said casing has formed therein four of said slits disposed equiangularly around th casing axis.

3. The writing implement as claimed in claim 2, wherein two of said strips of resilient material are oppositely disposed to each other with respect to the axis of the casing, said two strips of resilient material each having a greater longitudinal dimension than the other two resilient materials, and said two strips of resilient materials each having one said rim formed thereon.

4. The writing implement as claimed in claim 3, wherein the axially inner surfaces of said rims are coplanar with the axially outer surfaces of the other two strips of resilient material which do not have rims.

5. The writing implement as claimed in claim 4, wherein said friction means comprises an annulus of friction material frictionally seated in a ring-shaped enlarged portion of the bore of the casing. 

1. A writing implement comprising a one-piece tubular casing having a bore extending from its front end to its rear end, a plurality of slits formed in said casing, said slits extending longitudinally forwardly from the rear end of said casing to define short strips of resilient material between adjacent slits and which constitute the rear portion of the casing, an inwardly extending rim formed at the rear end of at least one of said strips of resilient material, a plurality of cartridges positioned in end-to-end abutting axially aligned relationship in said casing, each of said cartridges carrying a writing element at its forward end, said cartridges being individually insertable into said casing through the rear end of said casing by spreading said strips of resilient material radially outwardly and being individually removable from the front end of said casing, and friction means provided in an enlarged portion of the bore of the casing at its front end and frictionally engaging the forwardmost cartridge to hold it in the casing while permitting relative movement between said casing and the forwardmost cartridge when insertion or writing force is applied to the cartridge, the arrangement being such that in use, the writing element of the forwardmost cartridge projects beyond said front end of said casing and is restrained from rearward movement by the abutting condition of the remaining cartridges and the engagement of the rearmost cartridge with said rim, said rim engaging the rear of the rearmost cartridge as a stop to further rearward movement upon application of pressure to the cartridges during the writing operation.
 2. The writing implement as claimed in claim 1, wherein said casing has formed therein four of said slits disposed equiangularly around the casing axis.
 3. The writing implement as claimed in claim 2, wherein two of said strips of resilient material are oppositely disposed to each other with respect to the axis of the casing, said two strips of resilient material each having a greater longitudinal dimension than the other two resilient materials, and said two strips of resilient materials each having one said rim formed thereon.
 4. The writing implement as claimed in claim 3, wherein the axially inner surfaces of said rims are coplanar with the axially outer surfaces of the other two strips of resilient material which do not have rims.
 5. The writing implement as claimed in claim 4, wherein said friction means comprises an annulus of friction material frictionally seated in a ring-shaped enlarged portion of the bore of the casing. 